Method of forming dies



Dec. 30, 1952 N T, HERMANN 2,623,417

METHOD OF FORMING DIES Original Filed March 18, 1949 i uwe/vro/e N. 7: HERMAN/V ATTORNEY Patented Dec. 30, 1952 METHOD OF FORMING DIES Norman T. Hermann, Eatontown, N. .L, assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Original application March 18, 1949, Serial No. 82,116. Divided and this application May 6, 1950, Serial No. 160,473 1 2 Claims.

1 This invention relates to a method of forming a die, particularly of the material blanking type.

This is a division of the applicants copending application, Serial No. 82,116, filed March is,

1949, now Patent No. 2,568,152.

One of the factors determining the cost of parts blanked from material is the initial and maintenance costs of the dies by the aid of which the parts are produced. Conventional dies, formed of steel and requiring considerable expense, time and skilled labor for their initial manufacture, may be ground a limited number of times to recondition them for further use, after which the die is destroyed and a completely new die must be provided.

An object of the invention is to provide a method of forming a die which is simple in structure, inexpensive to manufacture and the major portion of which may be utilized indefinitely.

With this and other objects in view, the invention comprises a method of forming a die having a permanent member with an aperture positioned in alignment with a punch, and a metal strip having an aperture therein conforming to the contour of the punch. The first step of the method includes positioning the metal strip on the permanent member with its aperture in alignment with the punch and lowering the punch through the apertures of the strip and member. The lower end of the aperture in the member is temporarily sealed after which this aperture is filledwith a molten metal which is allowed to solidify about the punch, thereby forming an aperture cooperating with the aperture in the strip to form a die cavity in the member. After the die is formed, the punch removed therefrom, and the lower end of the aperture in the member opened, additional strips may be punched to form apertures therein for reconditioning the die. These strips in the present embodiment of the invention are spring steel which will withstand considerable wear. After the strip is worn by continued use of the die, the metal filling the aperture of the member may be melted and the worn strip replaced by a new strip. The aperture in the member may again be filled about the punch, utilizing, if desired, the former soft metal initially placed in the aperture, requiring only the addition of another apertured strip.

Other objects and advantages will be apparent from the following detailed description, when considered in conjunction with the accompanying drawings, wherein:

Fig. 1 is a front elevational view of the die shown in cooperation with a punch; and

Fig. 2 is a top plan view of the die.

Referring now to the drawing, numeral 10 designates a mounting plate which may be secured to the bed of a punch press, the mounting plate having an aperture H therethrough which may also be aligned with the conventional aperture in the bed of the press. The press includes the conventional ram 12 which is reciprocated in a given path during the operating cycles of the press. The ram carries a tool holder 14 mounted for vertical movement with the ram and the conventional guide sleeves [5 associated with guide pins 16 extending vertically from the mounting plate I0. A punch 18 is carried by the tool holder l4 and is of a given cross-sectional contour depending upon the contour of the part to be blanked.

The die includes a permanent member 20 mounted by the aid of screws 2| on the mounting plate I0 and provided with a central aperture 22 extending to a position short of the bottom of the main member where it opens into an aperture 23 registering with the aperture I I of the mounting plate. Aligned grooves 25 are formed in the upper surface of the member 20 to receive an apertured strip 26. The strip 26 is formed of spring steel and has an aperture 21 therein conforming to the contour of the punch 18, the aperture having been previously formed therein by the punch 18. This could be accomplished in either of two ways; one, by the use of an old type dlie which is to be replaced by the new die or; two, by the use of a die composed of the mounted member 20, with the apertures II and 23 temporarily closed and the aperture 22 filled with a molten metal about the punch. When the metal has cooled and the punch is withdrawn, the initial strip 26 may be punched. Prior to carrying out the method steps of forming the die, the metal in the aperture is fused and allowed to pass therefrom. The method is practiced by placing the strip 6 centrally of the member 20 so that it will intersect the top portion of the aperture 22 and have its ends rest in the grooves 25 to constitute the upper portion of the die and provide the main or cutting portion of the die cavity. The remaining portion 28 of the die is formed of a softer material, that is, a metal having a lower melting point than any of the other portions of the die. This metal is commercially known and is similar to lead.

The next step of the method of forming the die includes temporarily closing the lower end of the aperture 22 by filling the aperture II with a suitable material, such as a sealing compound 30. With the strip 26 in position in alignment with the punch 15, the punch is lowered until its leading end rests upon or is embedded in the sealing compound 99. The next step of the method includes filling the aperture 22 with the molten metal 23 having a lower melting point than the metals of the other portions of the die. The material or metal 28 will surround and conform to the punch completing a die cavity which is accurate in conforming to the punch and which 7 will require no machining. The molten metal disposed in the aperture 22 will extend upwardly along the side edges of the strip 29 and in this manner firmly secure the strip asa solid unit with the other members of the die. 1

When the material 28 has solidified and cooled suificiently, the punch 18 may be removed, after which the sealing compound 39 may be removed from the aperture l l completing the formation of the die. The die is now ready for use and may be used repeatedly until the strip 25 becomes worn. If desired, the die may be machined in the conventional manner by grinding the strip 25. However, the cost of reconditioning the die would be less expensive than grinding the die or strip. The die may be reconditioned by melting the material 29, removing the worn strip 25 and substituting a new strip 25 therefor. Reconditioning of the die requires only a supply of the strips 26 which may be produced at any time by the punch and die itself.

It is to be understood that the above described arrangements are simply illustrative of the application of the principl sof the invention. Numerous other arrangements. may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. The method of reconditioning a die having an apertured member supporting the outer portions of a metal strip apertured to conform to a punch, the intermediate portion of the metal strip being supported by a metal filling the aperture of the member and having a lower melting point than the member or the strip, the method comprising punching an aperture in a second metal strip with the punch and die, melting the metal in the aperture of the member and allowing it to flow therefrom, removing the first metal strip from the member, placing the second metal strip on the member with the aperture therein in alignment with the punch, lowering the punch through the apertures of the second strip and the member, filling the aperture of the member around the punch with a molten metal having a melting point lower than the member and strip, allowing the metal to cool and then removing the punch.

2. The method of reconditioning a die having an apertured member supporting the outer portions of a metal strip apertured to conform to a punch, the intermediate portion of the metal strip being supported by a metal filling the aperture of the member and having a lower melting point than the member or the strip, the method comprising punching an aperture in a second metal strip with the punch and die, melting the metal in the aperture of the member and allowing it to flow therefrom, removing the first metal strip from the member, temporarily closing the lower end of the aperture in the member, placing the second metal strip on the member with the aperture therein in alignment with the punch, lowering the punch through the apertures of the second strip and the member, filling the aperture of the member around the punch with a molten metal having a melting point lower than the member and strip, allowing the metal to cool and then removing the punch.

NORMAN T. HERNLAIQN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 486,858 Cummins Nov. 29, 1892 522,953 Bradley July 10, 1894 598,867 Hartog, Jr Feb. 8, 1898 623,595 C'laussen' Apr. 25, 1899 994,463 Hartog June 6, 1911 1,043,867 Queneau Nov; 12, 1912 1,089,724 Remnsni'der Mar. 10, 1914 1,118,189 radley Nov. 24, 1914 1,179,155 Bennett Apr. 11, 1916 1,325,194 Geist Dec. 16, 1919 1,453,278 Kucera May 1, 1923 1,505,336 Hartog Aug. 19, 1924 1,549,659 Cochran Aug. 11, 1925 1,997,292 Baker Apr. 9, 1935 2,161,597 Swartz -4 June 6, 1939 2,323,949 Vosburg July 13, 1943 2,395,082 Wilson Feb. 19, 1946 2,395,083 Wilson Feb. 19, 1946 OTHER REFERENCES The C'erromatrix Manual by Cerro De .Pasco Copper Corporation, 40 Wall Street, New York, N. Y., 1939. 

